The present control valve is one which is capable of handling the flow of solid and semi-solid material, highly erosive in nature, in temperature ranges from ambient to 200.degree. F. and higher. Such valves find applications in processes handling cold slurries, such as liquefaction or gasification, processes handling raw shale such as the extraction of shale oil, and for handling similar erosive materials such as the cataysts used in refining of crude oil. Numerous design of slide valves have been suggested and used for such solids flow; however, these valves have not been entirely satisfactory since they are not control valves in the true sense in that they are designed to modulate over a narrow flow range, rather than a full controlled range, and they are not capable of providing full pipe opening for solids dumping. The present invention overcomes these disadvantages and provides controlled flow over a full range, closing and complete opening for dumping of solids buildup.
The following patents were developed in a search directed to the present invention: U.S. Pat. Nos. 132,974; 2,787,438; 3,307,574; 3,701,359; 3,976,094; and 4,253,487; and Russian Pat. No. 571,647. None of these patents, however, discloses the inventive combinations, modes of operation and advantageous results thereof as set forth in the claims hereof.